722728 has 16 divisors (see below), whose sum is σ = 1378260. Its totient is φ = 355200.

The previous prime is 722723. The next prime is 722737. The reversal of 722728 is 827227.

It can be written as a sum of positive squares in 2 ways, for example, as 643204 + 79524 = 802^2 + 282^2 .

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 722696 and 722705.

It is not an unprimeable number, because it can be changed into a prime (722723) by changing a digit.

722728 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 253 + ... + 1228.

2⁷²²⁷²⁸ is an apocalyptic number.

It is an amenable number.

722728 is a deficient number, since it is larger than the sum of its proper divisors (655532).

722728 is a wasteful number, since it uses less digits than its factorization.

722728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1548 (or 1544 counting only the distinct ones).

The product of its digits is 3136, while the sum is 28.

The square root of 722728 is about 850.1341070678. The cubic root of 722728 is about 89.7411492321.

The spelling of 722728 in words is "seven hundred twenty-two thousand, seven hundred twenty-eight".